Enter the parked bus in northeast Fort Law to find out that it is rigged with explosives and will explode if you drop your speed too much! You must continue driving fast down roads without stopping until the explosives become unarmed. After, Bubby needs a couple of Mundanos down at Ardler Docks.
N, S, E, W = Compass Navigation
Small, Big = Small road or Big road.
Follow = You will start heading on a road in one direction, but at the end will follow the road's only turn to head into another direction.
(Keep speed up!) Just N, W big, S big till bomb off.
Steal Mundano, S big, E small just under bridge, E big over bridges.
After big bridge, S small, W small (follow), W small.
Back to road to steal Mundano again.